The general thrust of this research is to extend the study of the structure-function relationship in biological systems to the near limit of present-day time response. Using picosecond pulse technology with streak camera detection, subnanosecond fluorescence probe spectroscopy will constitute the major methodology employed. Second, third, and fourth harmonic generation of the primary 1060 nM laser output will allow the use of well-known fluorescence probes such as ANS, as well as others such as rose bengal. Four goals are envisioned: (1) To retrace the steps of nanosecond fluorescence probe experiments in biology during the past decade, supplementing and perhaps modifying these important results with this much-improved time resolution, (2) To compare subnanosecond results on systems of great biological importance with conclusions reached using spin label experiments, (3) To extend the study of active sites and functional groups in macromolecules and membranes (a) To motions on very rapid ( less than 100 psec) time scales and (b) To detailed anisotropic motions, and (4) To study the influence of drugs, antibiotics, and poisons on these motions in order to learn as much as possible about relationships that may exist between this microdynamical structure, biological function, and the understanding and control of disease.